This operator may be used as a postfix unary operator in an expression like x(*). The user may install a method for handling such expressions with code such as
X (*) := (x) -> ...
where X is the class of x.
The source of this document is in /build/reproducible-path/macaulay2-1.25.06+ds/M2/Macaulay2/packages/Macaulay2Doc/operators.m2:476:0.